Absence of mutations associated with resistance to benzimidazole in the beta-tubulin gene of Ascaris suum.

INTRODUCTION: Benzimidazoles are commonly used for the control of veterinary nematodes. Resistance to benzimidazoles has been associated with three single nucleotide polymorphisms in the ß-tubulin gene of common nematodes. However, these mutations are infrequent in the genus Ascaris spp. METHODS: In order to determine mutations associated with benzimidazole resistance in Ascaris suum, worms were collected from slaughtered pigs and a partial region of the ß-tubulin gene was sequenced. RESULTS: All parasites showed the wildtype genotype for codons 167, 198, and 200 of the ß-tubulin gene. CONCLUSIONS: This is the first report of genetic sequences associated with benzimidazole resistance in A. suum.

Absence of mutations associated with resistance to benzimidazole in the beta-tubulin gene of Ascaris suum

Abstract INTRODUCTION: Benzimidazoles are commonly used for the control of veterinary nematodes. Resistance to benzimidazoles has been associated with three single nucleotide polymorphisms in the β-tubulin gene of common nematodes. However, these mutations are infrequent in the genus Ascaris spp. METHODS: In order to determine mutations associated with benzimidazole resistance in Ascaris suum, worms were collected from slaughtered pigs and a partial region of the β-tubulin gene was sequenced. RESULTS: All parasites showed the wildtype genotype for codons 167, 198, and 200 of the β-tubulin gene. CONCLUSIONS: This is the first report of genetic sequences associated with benzimidazole resistance in A. suum.

Immune Profile of Honduran Schoolchildren with Intestinal Parasites: The Skewed Response against Geohelminths.

Soil-transmitted helminth infections typically induce a type-2 immune response (Th2), but no immunoepidemiological studies have been undertaken in Honduras, an endemic country where the main control strategy is children's annual deworming. We aimed to characterize the immune profile of Honduran schoolchildren harbouring these parasitoses. Demographic and epidemiological data were obtained through a survey; nutritional status was assessed through anthropometry; intestinal parasites were diagnosed by formol-ether and Kato-Katz; and blood samples were collected to determine immunological markers including Th1/Th2 cytokines, IgE, and eosinophil levels. A total of 225 children participated in the study, all of whom had received deworming during the national campaign five months prior to the study. Trichuriasis and ascariasis prevalence were 22.2% and 20.4%, respectively. Stunting was associated with both age and trichuriasis, whereas ascariasis was associated with sex and household conditions. Helminth infections were strongly associated with eosinophilia and hyper-IgE as well as with a Th2-polarized response (increased levels of IL-13, IL-10, and IL4/IFN-γ ratios and decreased levels of IFN-γ). Pathogenic protozoa infections were associated with a Th1 response characterized by elevated levels of IFN-γ and decreased IL10/IFN-γ ratios. Even at low prevalence levels, STH infections affect children's nutrition and play a polarizing role in their immune system.

Interleukin-10 and soil-transmitted helminth infections in Honduran children.

BACKGROUND: Soil-transmitted helminths (STH) establish chronic infections in the human intestine. The host reacts to these infections with a dominant T-helper type 2 cell (Th2) response that while attempting to control the worm population, can also provide an anti-inflammatory environment favourable for parasite survival. Regulatory cytokine interleukin 10 (IL-10) has been proposed as a key molecule involved in the attenuation of chronic inflammation and the ensuing tolerance for these helminth parasites. The objective of this study was to determine whether STH-infected children from an endemic community had increased circulating IL-10 levels when compared to non-infected children. RESULTS: A total of 39 children (25 boys and 14 girls, 7-15 years of age) were enrolled in study. Utilizing the Kato-Katz method to detect intestinal helminthiases, 10 children were non-infected and 29 were harbouring STH infections by Ascaris lumbricoides, Trichuris trichiura and/or hookworms. Of the 29 infected children, 11 had single-species infections and 18 were polyparasitized with two or three STH species. Serum samples from all 39 children were tested for IL-10 serum concentrations, out of which 12 had undetectable levels while 27 had levels ranging from 0.4-105 pg/mL. Excluding extreme outlying values, 25 samples had IL-10 concentration values ranging from 0.4 -7.2 pg/mL. Differences in IL-10 levels among non-parasitized, monoparasitized, and polyparasitized groups were not statistically significant. However, children infected with any of the three STH species investigated had higher IL-10 levels than non-parasitized children (geometric means: 0.89 pg/mL vs. 0.74 pg/mL, p = 0.428). Similarly, polyparasitized children had higher IL-10 levels than both monoparasitized and non-parasitized children (1.04 pg/mL, 0.69 pg/mL, and 0.74 pg/mL, respectively, p = 0.481). A significant moderate negative correlation between IL-10 levels and children's age was found, but no correlations were observed between IL-10 levels and intensity of infection by any of the parasite species investigated. CONCLUSIONS: We found no strong evidence for an association between STH infection and serum IL-10 concentration levels. However, the trends identified here warrant further investigation. Additional research is needed to expand the current understanding of the immune response elicited by STH infections in children living in endemic communities.

A PCR-RFLP method for the simultaneous differentiation of three Entamoeba species.

Amoebiasis caused by Entamoeba histolytica continues to be one of the most common parasitic diseases in the developing world. Despite its relevance, due to the lack of accurate diagnostic methods, the true clinical and public health importance of this parasite remains uncertain. The aim of this study was to develop a new diagnostic tool to differentiate E.histolytica from the morphologically undistinguishable E.dispar and E.moshkovskii. We developed a specific, fast and simple PCR-RFLP method that was able to accurately differentiate experimentally-obtained restriction patterns from the three Entamoeba species. This new method could prove useful for clinical and epidemiological purposes.

School hygiene and deworming are key protective factors for reduced transmission of soil-transmitted helminths among schoolchildren in Honduras.

BACKGROUND: Among many neglected tropical diseases endemic in Honduras, soil-transmitted helminth (STH) infections are of particular importance. However, knowledge gaps remain in terms of risk factors involved in infection transmission. The aim of this study was to investigate risk factors associated with STH infections in schoolchildren living in rural Honduras. METHODS: A cross-sectional study was conducted among Honduran rural schoolchildren in 2011. Demographic, socio-economic, and epidemiological data were obtained through a standardized questionnaire and STH infections were determined by the Kato-Katz method. Logistic regression models accounting for school clustering were used to assess putative risk factors for infection. RESULTS: A total of 320 children completed the study. Prevalences for any STH and for Ascaris lumbricoides, Trichuris trichiura and hookworms were: 72.5%, 30.3%, 66.9% and 15.9%, respectively. A number of risk factors were identified at the individual, household, and school level. Boys were at increased odds of infection with hookworms (OR 2.33, 95% CI = 1.23-4.42). Higher socio-economic status in the family had a protective effect against infections by A. lumbricoides (OR 0.80, 95% CI = 0.65-0.99) and T. trichiura (OR 0.77, 95% CI = 0.63-0.94).Low school hygiene conditions significantly increased the odds for ascariasis (OR 14.85, 95% CI = 7.29-30.24), trichuriasis (OR 7.32, 95% CI = 3.71-14.45), mixed infections (OR 9.02, 95% CI = 4.66-17.46), and ascariasis intensity of infection (OR 3.32, 95% CI = 1.05 -10.52).Children attending schools not providing deworming treatment or that had provided it only once a year were at increased odds of ascariasis (OR 10.40, 95% CI = 4.39-24.65), hookworm (OR 2.92, 95% CI = 1.09-7.85) and mixed infections (OR 10.57, 95% CI = 4.53-24.66). CONCLUSIONS: Poverty-reduction strategies will ultimately lead to sustainable control of STH infections in Honduras, but as shorter-term measures, uninterrupted bi-annual deworming treatment paired with improvements in school sanitary conditions may result in significant reductions of STH prevalence among Honduran schoolchildren.

Employers' paradoxical views about temporary foreign migrant workers' health: a qualitative study in rural farms in southern Ontario.

BACKGROUND: The province of Ontario hosts nearly a half of Canada's temporary foreign migrant farm workers (MFWs). Despite the essential role played by MFWs in the economic prosperity of the region, a growing body of research suggests that the workers' occupational safety and health are substandard, and often neglected by employers. This study thus explores farm owners' perceptions about MFWs occupational safety and general health, and their attitudes towards health promotion for their employees. METHODS: Using modified grounded theory approach, we collected data through in-depth individual interviews with farm owners employing MFWs in southern Ontario, Canada. Data were analyzed following three steps (open, axial, and selective coding) to identify thematic patterns and relationships. Nine employers or their representatives were interviewed. RESULTS: Four major overarching categories were identified: employers' dependence on MFWs; their fragmented view of occupational safety and health; their blurring of the boundaries between the work and personal lives of the MFWs on their farms; and their reluctance to implement health promotion programs. The interaction of these categories suggests the complex social processes through which employers come to hold these paradoxical attitudes towards workers' safety and health. There is a fundamental contradiction between what employers considered public versus personal. Despite employers' preference to separate MFWs' workplace safety from personal health issues, due to the fact that workers live within their employers' property, workers' private life becomes public making their personal health a business-related concern. Farmers' conflicting views, combined with a lack of support from governing bodies, hold back timely implementation of health promotion activities in the workplace. CONCLUSIONS: In order to address the needs of MFWs in a more integrated manner, an ecological view of health, which includes the social and psychological determinants of health, by employers is necessary. Employers and other stakeholders should work collaboratively to find a common ground, harnessing expertise and resources to develop more community-based approaches. Further research and continuous dialogue are needed.

A scoping review and prevalence analysis of soil-transmitted helminth infections in Honduras.

BACKGROUND: Honduras is endemic for soil-transmitted helminth (STH) infections, but critical information gaps still remain on the prevalence and intensity of these infections as well as on their spatial distribution at subnational levels. OBJECTIVES: Firstly, to review the research activity on STH infections in Honduras and secondly, to carry out a national prevalence analysis and map the geographical distribution of these infections in children. METHODS: A systematic search was conducted of the published and grey literature to identify scientific work on the impact and prevalence of STH infections done between May 1930 and June 30, 2012. International databases and Honduran journals were searched. Grey literature was gleaned from local libraries and key informants. Select studies conducted between 2001 and 2012 were used to produce prevalence maps and to investigate association between STH prevalence and socio-economic and environmental factors. RESULTS: Of 257 identified studies, 211 (21.4% peer-reviewed) were retained for analysis and categorized as clinical research (10.9%), treatment efficacy studies (8.1%) or epidemiological studies (81%). Prevalence analysis and geographical mapping included 36 epidemiological studies from Honduras's 18 departments and 23% of its municipalities. Overall STH prevalence was >50% in 40.6% of municipalities. Prevalences above 20% for each trichuriasis, ascariasis, and hookworm infection were found in 68%, 47.8%, and 7.2% of studied municipalities, respectively. Municipalities with lower human development index, less access to of potable water, and with higher annual precipitation showed higher STH prevalences. CONCLUSIONS: This is the first study to provide a comprehensive historic review of STH research activity and prevalence in Honduras, revealing important knowledge gaps related to infection risk factors, disease burden, and anti-parasitic drug efficacy, among others. Our decade-long prevalence analysis reveals geographical differences in STH prevalence and these findings suggest that differential intervention strategies might be necessary in Honduras for the control of these infections.

A research capacity strengthening project for infectious diseases in Honduras: experience and lessons learned.

BACKGROUND: In Honduras, research capacity strengthening (RCS) has not received sufficient attention, but an increase in research competencies would enable local scientists to advance knowledge and contribute to national priorities, including the Millennium Development Goals (MDGs). OBJECTIVE: This project aimed at strengthening research capacity in infectious diseases in Honduras, focusing on the School of Microbiology of the National Autonomous University of Honduras (UNAH). The primary objective was the creation of a research-based graduate program for the continued training of researchers. Parallel objectives included institutional strengthening and the facilitation of partnerships and networks. METHODS: Based on a multi-stakeholder consultation, an RCS workplan was designed and undertaken from 2007 to 2012. Due to unexpected adverse circumstances, the first 2 years were heavily dedicated to implementing the project's flagship, an MSc program in infectious and zoonotic diseases (MEIZ). In addition, infrastructure improvements and demand-driven continuing education opportunities were facilitated; biosafety and research ethics knowledge and practices were enhanced, and networks fostering collaborative work were created or expanded. RESULTS: The project coincided with the peak of UNAH's radical administrative reform and an unprecedented constitutional crisis. Challenges notwithstanding, in September 2009, MEIZ admitted the first cohort of students, all of whom undertook MDG-related projects graduating successfully by 2012. Importantly, MEIZ has been helpful in expanding the School of Microbiology's traditional etiology-based, disciplinary model to infectious disease teaching and research. By fulfilling its objectives, the project contributed to a stronger research culture upholding safety and ethical values at the university. CONCLUSIONS: The resources and strategic vision afforded by the project enhanced UNAH's overall research capacity and its potential contribution to the MDGs. Furthermore, increased research activity and the ensuing improvement in performance indicators at the prime Honduran research institution invoke the need for a national research system in Honduras.

Soil-transmitted helminth infections and nutritional status in school-age children from rural communities in Honduras.

BACKGROUND: Soil-transmitted helminth (STH) infections are endemic in Honduras and efforts are underway to decrease their transmission. However, current evidence is lacking in regards to their prevalence, intensity and their impact on children's health. OBJECTIVES: To evaluate the prevalence and intensity of STH infections and their association with nutritional status in a sample of Honduran children. METHODOLOGY: A cross-sectional study was done among school-age children residing in rural communities in Honduras, in 2011. Demographic data was obtained, hemoglobin and protein concentrations were determined in blood samples and STH infections investigated in single-stool samples by Kato-Katz. Anthropometric measurements were taken to calculate height-for-age (HAZ), BMI-for-age (BAZ) and weight-for-age (WAZ) to determine stunting, thinness and underweight, respectively. RESULTS: Among 320 children studied (48% girls, aged 7-14 years, mean 9.76 ± 1.4) an overall STH prevalence of 72.5% was found. Children >10 years of age were generally more infected than 7-10 year-olds (p = 0.015). Prevalence was 30%, 67% and 16% for Ascaris, Trichuris and hookworms, respectively. Moderate-to-heavy infections as well as polyparasitism were common among the infected children (36% and 44%, respectively). Polyparasitism was four times more likely to occur in children attending schools with absent or annual deworming schedules than in pupils attending schools deworming twice a year (p<0.001). Stunting was observed in 5.6% of children and it was associated with increasing age. Also, 2.2% of studied children were thin, 1.3% underweight and 2.2% had anemia. Moderate-to-heavy infections and polyparasitism were significantly associated with decreased values in WAZ and marginally associated with decreased values in HAZ. CONCLUSIONS: STH infections remain a public health concern in Honduras and despite current efforts were highly prevalent in the studied community. The role of multiparasite STH infections in undermining children's nutritional status warrants more research.

Estudio epidemiológico en teniasis y cisticercosis en Honduras / Epidemiological study of taeniasis and cysticercosis in Honduras

Con el objetivo de determinar la prevalencia de las infecciones por taenia solium y los factores de riesgo asociados a la teniasis y la cisticercosis en una población de residencia urbana en Honduras, se realizó un estudio en la población, tanto militar como civil de una institución militar situada en Tegucigalpa. Se tomó una muestra de sangre para determinación de anticuerpos séricos mediante la prueba de Electroinmunotransferencia (EITB) o Western blot, y se colectaron 2-3 muestras de heces seriadas para investigación de teniásis por medio del método de concentración de formoléter. Se obtuvo información epidemiológica, médica, social y demográfica de cada participante. Se ingresaron al estudio 404 personas, entre 18 y 65 años de edad, 83 por ciento del sexo masculino y 17 por ciento del sexo femenino. 22 por ciento eran civiles y 78 por ciento militares. El 10 por ciento no había concluído los estudios de educación primaria, el 26 por ciento si lo había completado y el 64 por ciento tenía además estudios de educación media y/o universitaria. 24 por ciento de la población residia en el cuartel (principalmente soldados y reclutas); 68 por ciento tenía piso de ladrillo y 32 por ciento de tierra o mixto; 90 por ciento tenía acceso a agua potable y energía eléctrica; 23 por ciento poseía letrinas y 77 por ciento servicio sanitario; 6 por ciento reportó que en su casa criaban cerdos. 6 por ciento de los entrevistados reportó haber padecido de teniásis; 5 por ciento admitió que alguien de su familia tenía o había tenido teniásis. De 404 los entrevistados, 328 enviaron las muestras de heces para su análisis. Se encontraron dos casos de teniásis (0.6 por ciento) en dos soldados, uno de estos casos de identificó como T. solium. se analizaron 404 muestras de suero (100 por ciento de la población), encontrándose una seropositividad general de 20.5 por ciento (83/404). Aunque sin el auxilio de las imágenes es imposible precisar si esta seropositividad se debe al contacto pasado con el parásito o a la presencia actual de cisticercosis en el SNC o fuera de él, el alto número de seropositivos demuestra el frecuente contacto de la población con Taenia solium, y alerta sobre la posibilidad de que alguna de las personas seropositivas pueda desarrollar síntomas en el futuro.

Infección por isospora belli: presentación de tres casos / Isopora belli's infection: presentation of 3 cases

Se describen tres casos clínicos de infección por isospora belli en pacientes pediátricos que presentaban algunas características comunes como la condición socioeconómica de marginalidad, estado nutricional deficiente y antecedentes de problemas gastrointestinales. El diagnóstico fue establecido en el laboratorio por medio de exámenes coproparasitológicos con el método directo en dos de los casos y con un método de concentración el restante. En uno de los casos se hizo el seguimiento y tratamiento adecuado con trimetroprim sufatometoxazole por ser un caso institucionalizado, comprobando la erradicación del parásito y el mejoramiento del estado nutricional del infante. Es importante señalar que en nuestro medio ésta parasitosis puede representar una frecuencia mayor de la conocida actualmente, debido tanto a la dificuldad de establecer el diagnóstico clínico por la variedad de organismos patógenos que pueden producir un cuadro similar, como por la baja sensibilidad del método directo que es utilizado de rutina en los laboratorios

Infección por isospora belli: Presentación de tres casos / Isospora belli's infection: Presentation of three cases

Se describen tres casos clínicos de infección por isospora belli en pacientes pediátricos que presentaban algunas características comunes como la condición socioeconómica de marginalidad, estado nutricional deficiente y antecedentes de problemas gastrointestinales. El diagnóstico fué establecido en el laboratorio por medio de exámenes coproparasitológicos con el método directo en dos de los casos y con un método de concentración el restante. En uno de los casos se hizo el seguimiento y tratamiento adecuado con trimetroprim sufatometoxazole por ser un caso institucionalizado, comprobando la erradicación del parásito y el mejoramiento del estado nutricional del infante. Es importante señalar que en nuestro medio esta parasitosis puede representar una frecuencia mayor de la conocida actualmente, debido tanto a la dificultad de establecer el diagnóstico clínico por la variedad de organismos patógenos que pueden producir un cuadro similar, como por la baja sensibilidad del método directo que es utilizado de rutina en los laboratorios